...
At the present time Mars topography is known sufficiently well to make a
Martian map; we cannot distinguish yet the settlements of the
inhabitants of this planet, but sooner or later we probably will be able
to achieve this as well...

...Does
a biosphere exist on Mars? The totality of all known facts about the
Martian atmosphere and surface does not seem to give any chance for
that. However, could life be so"quietly
burning" on Mars that its power would not be enough to create a
noticeable biosphere? Let us hope that a day will come when the answer
to the fundamental question "is there life on Mars" will
become known...

In
April 7th, 2001, NASA launched the spacecraft "2001 Mars
Odyssey" to Mars. It was the 33rd launch to Mars since
October 1960, when Soviet Union made the first, but unsuccessful,
attempt to fly to the Red planet. US spacecraft "Mariner-4"
performed the first successful flyby and transmitted to the Earth twenty
one photos of Mars' surface.In
December 3, 1971 the Soviet space probe "Mars-3" landed on
Mars and transmitted the first scientific data on the surface conditions.
In 1976, two US landers "Viking-1" and "Viking-2"
performed a comprehensive search for traces of life on Mars. During
three months of 1997, the miniature rover "Sojourner" made a
detailed inspection of the vicinity of the landing spot of the US "Mars
Pathfinder". The NASA (USA), European Space Agency and Russian
Aviation and Space Agency (Rosaviakosmos) have plans of future Mars
exploration in 2003, 2005, 2007 and so on into the future.

Why
do people want to explore Mars?

It
is considered conventional wisdom that Earth and Mars were created from
a proto-planetary cloud around the young Sun about 4.6 billion years ago.
According to one of the current theories both planets had practically
the same evolution during the early stages of their life. Large oceans
were spreading out on the warm surfaces of these planets; chemically
complicated gases from frequent explosions of large volcanoes enriched
the thick and dense atmosphere. However, after some hundreds of million
years the conditions on Mars have transformed from the "warm-and-wet"
state into a "cold-and-dry"
one. Was the reason of this change a collision with a large asteroid,
which re-orientated the polar axis or even changed the orbit of Mars? Or
maybe this transformation is the result of some global climate change
during the time when the planet gradually lost its thick and warm
atmosphere because of weak gravity? Finally, Mars became cold, and the
most of the water has stayed only at north polar cap or in permafrost
regions. The Martian atmosphere became thin, dry and cold.

The
first goal of Mars exploration is to understand the reason for planet
transformation from an early "warm-and-wet" state into the
present "cold-and-dry" one. The
solution of this problem will be important not only for the progress of
fundamental science of planetary evolution, but also for understanding
of the potential danger of a similar climatic catastrophe for
Earth.

The
recent data from the “Mars Global Surveyor”
and other missions shows that Mars is an active planet. It has the
largest volcano in the Solar System with a height of 27 km and the
largest canyon with a depth of about 10 km and length of about 5000 km.
The strength of local magnetic field is comparable with the Earth’s
one, but the Martian field has a rather complicated structure with local
loops. Recent photos show many gullies and ravines in craters and on
crater’s walls that maybe the results of water flow, which may be
resent or some millions of years ago. It is supposed that large
subsurface ice reservoirs or liquid water exist on Mars. There are also
many unusual features on the Martian surface (very flat terrains,
circular depressions, streamlined islands, possible shorelines, etc.),
whose formation may be impossible to explain without the existence of
flowing water in the past.

The
second goal of Mars exploration is the development of a detailed model
of the planet, which should incorporate the main data on the core,
crust,
subsurface layer, surface, and atmosphere, and which also should take
into account the main physical and chemical processes, which take place
there.

The
search for traces of
life on Mars is also important.

Firstly,
primitive life on a young "warm-and-wet"
Mars could be created as easily as it was in similar condition on young
Earth. Secondly, if subsurface water reservoirs exist on modern Mars,
parts of them may have heat and be enriched by gases from nearby active
volcanoes and be suitable for some form of life. It is known that some
microbes live in similar conditions on the Earth. Thirdly, recent
studies of some meteorites, which possibly were produced by the
collision of a comet or other cosmic voyager with Mars, shows that there
are some inclusions in these meteorites that are very similar to
fossilized microbes.

The
third goal of exploration of Mars, probably the most important one, is
the search for life on Mars now or any traces of biological processes in
the past. The discovery of evidence of life on Mars will become the
greatest scientific achievement.

The
direct comparison of biological structures of Mars and Earth will point
out the similarity or difference between them and, therefore, it will be
a direct check of the universality of biological laws on different
celestial bodies. On the other hand, the absence of any biological
activity on Mars, if it could be proved, should show the possible
uniqueness of terrestrial life in the Universe.

Finally,
Mars is the only planet in the Solar system, except the Earth, which
allows humans to be on its surface with rather simple life-supporting
equipment. Therefore, the prospecting of natural Martian resources (internal
planet heat, water, minerals, e. c.) "today” is the necessary
condition of human colonization of Mars "tomorrow".

The
"distant purpose" for research of Mars is developing of the
planet as a stage of further expansion of mankind in Space.

Therefore,
the exploration of Mars is associated with a fundamental problem of
mankind’s evolution. It is suppose that the mission "2001
Mars Odyssey" will make the next step in resolving them. As
it is mentioned above, the research of chemical composition of the
Martian surface is a key item of Mars exploration, especially including
the search for water (the NASA keystone strategy of "Following the
Water"). These investigations in during of mission will be
performed by the Gamma Ray Spectrometer (GRS), which includes the
Russian-made High Energy Neutron Detector (HEND) for detection of
high-energy neutrons.